Do not choose sour tomatoes. Blanch tomatoes (soak them in boiling water for 7-8 minutes, drain and peel them) and crush them with roasted coriander seeds in a food processor or blender and make a smooth tomato puree.

Heat 1-tablespoon oil in a pan or kadai. Shallow fry boiled potatoes until they turn slightly light brown. Transfer them to a plate and keep aside.

Heat remaining 2½ tablespoons oil in same pan over medium flame and add cumin seeds, cinnamon and bay leaves. When cinnamon and cloves begin to crackle, add chopped onion, chopped green chilli and grated ginger. Stir to mix well and sauté until onion’s color changes to light brown and oil starts to separate from it. Make sure to sauté over low to medium heat.